Association between environmental tobacco smoke exposure and diabetes: Results from the NHANES 2013-2016 and mendelian randomization analysis

The relationship between environmental tobacco smoke (ETS) exposure at different locations and diabetes remains unclear. We explored the abovementioned associations and combined mendelian randomization (MR) techniques to further investigate the causality. In this observational study, data collected by the National Health and Nutrition Examination Survey (NHANES) 2013-2016 were assessed, which included nonsmokers aged >= 20 years (n = 3749). Subsequently, MR analysis was performed using the inverse variance weighted (IVW) approach to assess the causal connection between different locations of ETS exposure and diabetes from the UK Biobank, DIAbetes Genetic Replication And Meta-analysis (DIAGRAM) consortium, and FinnGen datasets. Multivariate logistic regression analyses demonstrated that exposure to ETS outside the home was positively associated with diabetes in nonsmokers over 60 years (OR = 2.19; 95%CI, 1.19-4.02, p = 0.018). This positive connection was sustained in a subgroup analysis among females (OR = 3.19; 95%CI, 1.48-6.88, p = 0.006) but not in males. In the MR analysis, exposure to ETS outside the home was linked with an elevated risk of type 2 diabetes mellitus (OR = 4.52; 95%CI: 1.54-13.32, p = 0.006) according to the IVW outcomes. Findings from our observational study identified exposure to ETS outside the home might be associated with an increased risk of diabetes in nonsmokers, and further MR analysis revealed the causal associations between genetically predicted ETS exposure outside the home on T2DM.These findings assist the need for targeted strategies, including more compulsory smoke-free policies, to address this issue effectively.